As shown in FIG. 1, corn heads are provided with several row crop dividers for retrieving, lifting, and directing the rows of corn stalks toward their respective ear separation chambers.
As shown in FIG. 2, these crop dividers in combination with the gathering chain(s) and stripper plates assist the crop from near ground level into the ear separation and conveying chambers. Stripper plates further center the corn plant between two stalk rolls located beneath the stripper plates.
These stalk rolls, as illustrated by FIG. 3, are powered by the gearbox. As the stalk rolls rotate, the flutes on the stalk rolls pinch and pull the corn stalks downward. Two stripper plates located above the stalk rolls and on both sides of the corn row are spaced wide enough to allow the corn plant to pass between them but narrow enough to retain the ears of corn which contain grain. This causes the ears of corn to be separated from the corn plant as it is pulled rapidly between these stripping plates. The stalk rolls continue to rotate ejecting the unwanted portions of the corn plant below the ear separation chamber thereby returning them to the field. The ears of corn are then transferred by the gathering/conveying chain(s) into the next conveying system for delivery to the combine for ultimate threshing and separation of the corn kernels from the corncob, silks, and husks.
In the past thirty years, three external factors have impacted corn harvesting: (1) Environmentally friendly residue management rules mandate that the farmer keep a certain percentage of crop residue on the surface of the land to prevent soil erosion. (2) Yields have doubled through improved genetics, fertilization, populations, and row spacings. (3) Harvesting machines are larger with increased horsepower, capacity, ground speed and utilize corn heads with more row units.
These three factors in combination require that modern corn head row units: (1) Increase the speed of ear separation. (2) Ensure that the corn plant is not severed from its roots system. (3) Increase the speed at which ears are conveyed out of the row unit. (4) Increase the speed at which corn stalks are ejected from the row unit. (5) Retain minimal amounts of mote (material other than ears) in the heterogeneous material being delivered to the combine for threshing.
The performance of previous row units, as shown in FIG. 2, was limited in down corn for two reasons: 1) The front portion of the row unit covers were tall causing any unattached mass of tangled plants to stall when sliding up this steep inclined plane. 2) The current design does not allow the distance between the gathering chain and the row unit covers to be minimized. This distance hinders engagement of the mass of unattached tangled plants with the gathering chain paddles. The rear height of the prior art corn head row unit cover's single largest plane was more than fifty percent (50%) of the front height. For example, the Case IH metal rear row unit cover front height of the single largest plane was 11.625 inches. The rear height of this plane was 6.5 inches which is equivalent to an almost fifty-six percent (56%) ratio. Gathering chain paddles impart force to the mass of corn stalks in the row unit or on the row unit covers to propel them to the corn head cross auger for further conveyance.
In FIG. 1A prior corn head row units were limited by gathering chain(s) utilizing eight short paddles. These paddles did not adequately move the ears out of the row unit at high operating speeds due to large amounts of ear slippage because the ear of corn is taller than the paddle. Another factor causing ear slippage is that the paddles are too close together, therefore not allowing adequate time for the ear to fall in between the paddles during high-speed operation.
In FIG. 3, some row units of the prior art have stripper plates utilizing one flat surface for gathering and stripping ears. This limited performance because this surface doesn't emulate the shape of the arched portion of the bottom side of the leaf area causing unnecessary leaf detachment and retention. Some previous stripper plates utilized one-beveled surface for both gathering and stripping. This limited performance by hindering the flow of ears between the spirals of the nose cone of the stalk roll and the bottom side of the beveled stripping edge. This caused ears to wedge and plug the row unit.
Previous row units were limited because the rotating directional vanes or spirals on the helical nose cones were inter-related causing lateral whipping of the corn plant. In FIG. 3 attempts at increasing ear separation speed were made by increasing rotational speed of the stalk rolls. This was unsuccessful because the stalk roll flutes of the same length rotating at high speeds act like a solid rotating cylinder and do not allow the individual flutes to engage the corn stalk. Thus the corn stalk is repelled and stalls without entering the corn stalk ejection area of the stalk rolls. This is also sometimes referred to as an eggbeater effect. This stall allows the rotating flute edges to lacerate the corn plant. When the gathering chain paddle passes above the stripper plates and engages this stalled plant, it will break or sever the plant prior to ear separation. This stall also causes ear separation to take place near the opening of the row unit and allows loose ears to tumble to the ground thereby becoming irretrievable.
In FIG. 3 one major manufacturer's stalk rolls utilize six flutes which inter-mesh and overlap. When this type of stalk roll engages the corn stalk, the flutes alternately apply opposing force. This fluted design causes at least three problems which are described in FIG. 3: (1) The corn plants are violently tossed from side to side causing premature separation of loosely attached ears, thereby permitting the ear to fall to the ground and become irretrievable. (2) The corn stalk snaps at a node causing long unwanted portions of the stalk and leaves to stay attached to the ear and remain in the row unit. This eventually creates a pile of trash or fluff in front of the cross-auger and feeder house. This problem is compounded as the number of row units per corn head is increased. (3) The corn stalks are cut-off prior to ear separation. This is sometimes referred to as a scissor effect.
Another major manufacturer's stalk rolls utilize four adjustable non-meshing flutes with two adjustable nose bearings. Frequent adjustment is required because the leading edge(s) of the flutes wear rapidly increasing stalk roll to stalk slippage and eventually stalk hair pinning over row unit frames. Nose bearing adjustment is necessary because row unit frames fatigue, stretch or bend.
As shown in FIG. 3, it has been an objective of some prior art stalk rolls with knife edged flutes to simultaneously chop up or shred the corn stalks while returning them to the field. This allows faster decomposition of the crop residue and decreases the plugging of tillage tools. The detached crop residue washes, blows or rapidly decomposes so that there is no protection for the soil. Thereby leaving it exposed to wind and water erosion. It has now been determined that this type of crop residue management is not environmentally friendly.
Corn heads of the prior art utilize bolt on, non-adjustable tall end dividers. These end dividers plug in down corn.